Marble or lime plaster? A debate over this has hampered and delayed the work for 'functional restoration' of the 18th-century astronomical observatory Jantar Mantar.

Marble or lime plaster? A debate over this has hampered and delayed the work for 'functional restoration' of the 18th-century astronomical observatory Jantar Mantar.Years after documentation work for the Archaeological Survey of India (ASI) protected monument was completed, the agency was embroiled in a legal case over the use of material for all instruments' surfaces. Misra Yantra would now be the first one to undergo pilot work.

The Jantar Mantar (apparently a variation of the word Yantra Mantra, yantra for instrument and mantra for formula) is a set of masonry instruments that form an observatory, one of the five created by Maharaja Sawai Jaisingh II of Jaipur in the early 18th century. Taking the bonafide of petitioner Ravindra Nath Sharma into account, the Delhi High Court had two years ago ordered ASI to “work really hard towards making the observatory work again considering that it was a masterpiece of Indian architecture displaying scientific acumen of the era".

Making the observatory work again — or functional restoration — meant beyond conservation, people should be able to use all the instruments for taking readings such as time or finding positions of planets.

When the ASI dilly-dallied the matter, Nath filed a contempt petition, prompting the ASI to take faster steps. The issue was whether or not to have marble on the surface of the instruments. The ASI has now formed a special committee comprising N Ratnashree, director of Nehru Planetarium and representative of Science Popularisation Association of Communicators and Educators (both from Delhi) and astronomy experts from Bengaluru and Chennai.

“The texture is important as sub-surface reflection will differ in case of lime plaster and marble. Originally, Jantar Mantar had lime plaster but over the years, there have been several recommendations for use of marble. (But) we will stick to what is original," Ratnashree said.DN Dimri, ASI's Delhi circle chief said, “The meeting of these experts would be held soon and as per their recommendation, the work for conservation would begin."